1. Field of the Invention
The present invention relates to a winding apparatus, and in particular, to a winding apparatus for use in a copier, a printer, and other devices for ejecting a printed sheet rolled in the form of a cylinder without having a core.
2. Description of the Related Art
For an apparatus that prints a long sheet extending for several meters, such as a copier that prints advertisement or a long-format printer, one print method is to use a continuous sheet and to wind the sheet in roll form without cutting it after completing a single printing operation. In this method, the sheet is required to be cut afterward. Another print method is to cut a sheet with a cutter when a single printing operation is completed and to store the cut sheet on a flat output tray. In this method, an enormous space is required (see, for example, Japanese Patent Laid-Open No. 2002-356260).
A paper storage device that stores a sheet while rolling the sheet into cylindrical form has been proposed (see, for example, Japanese Patent Laid-Open No. 11-060018). Also a device for attaching tape onto the trailing end of a sheet to maintain a rolled state of the rolled sheet in cylindrical form has been proposed (see, for example, Japanese Patent Laid-Open No. 11-139636).
The paper storage device disclosed in Japanese Patent Laid-Open No. 11-060018 has a structure in which a pair of upstream rollers pushes a sheet into a storing unit disposed to roll sheets. Therefore, the storage device includes driving rollers at several points of the storing unit in order to prevent the sheet from buckling in process of being rolled. However, even with such a structure, very thin paper is in danger of buckling. In addition, because the driving rollers are rotated at a higher speed than the speed of conveying the sheet, in the case where a sheet of thick paper is used, the driving rollers may cause damage to the surface of the sheet.
Therefore, it would be desirable to provide a winding apparatus capable of rolling a sheet into cylindrical form for use in a copier, a printer, and other devices stably irrespective of the thickness of the sheet without causing the sheet to buckle or damaging the surface of the sheet.